The present disclosure relates generally to seal assemblies, and more particularly to floating non-contact seals for use in gas turbine engines.
Honeycomb and knife-edge seals can be used to form a seal at the interface between rotating and static components within the turbine section of a gas turbine engine. Over time, the knife-edge seal can wear a trench into the honeycomb causing gaps and sporadic leaks.
Floating non-contact seal (a.k.a., hydrostatic seal) configurations allow radial motion of shoe components relative to a rotating component. Floating non-contact seals can vary a gap between the sealing element and a rotating component by adjusting in response to to the change in pressure across the sealing element. A shoe component of the floating non-contact seal is drawn radially inward and outward (toward and away) from the rotating component in response to the pressure across the sealing element. In hydrostatic seals, a full ring portion of the seal connects to the beams and shoes of the seal. A full ring is needed to hold all of the shoes together, with respect to each other, in order to function properly as a full ring seal. In existing designs, this full ring is located outboard of and made integrally with the beams and the shoes. This location of the full ring adds considerable radial height to the seal assembly negatively impacting packaging within the turbine and jeopardizing beam thickness optimization that may degrade the performance and life of the seal system.
Structures and configurations of floating non-contact seals are the subject of the following commonly owned U.S. Patent Publications US2016/0130963A1, US2015/0322816A1, and US2015/0285152A1 (incorporated by reference herein in their entireties).